Merge pull request #6 from valiton/fix-bug-for-more-than-10-keys-aws-…

…limit

Fix bug for more than 10 keys aws limit

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@valiton/aws-param-inject",
-  "version": "1.0.2",
+  "version": "1.0.3",
   "description": "Simple tool to fetch and inject parameters from AWS SSM into a string.",
   "bin": "src/index.js",
   "main": "src/inject-ssm-params.js",

src/inject-ssm-params.js

@@ -2,11 +2,16 @@ const AWS = require("aws-sdk");
 
 const ssm = new AWS.SSM();
 
+// aws has a hard limit on the number of keys it can return and errors of there
+// are too many https://amzn.to/2QhXRTf
+const keyPerRequestLimit = 10;
 const ssmPattern = /\$\{ssm:.*?\}/g;
 const extractKey = match => match.slice(6, -1);
 
-const responseToMap = data =>
-  data.Parameters.reduce(
+const responseToParams = data => data.Parameters;
+
+const paramsToMap = params =>
+  params.reduce(
     (acc, current) => ({ ...acc, [current.Name]: current.Value }),
     {}
   );
@@ -17,21 +22,35 @@ const makeError = invalidParameters => {
   return new Error(errMsg);
 };
 
+const createChunks = (chunkSize, array) => {
+  const numberOfChunks = Math.ceil(array.length / chunkSize);
+  return Array.from({ length: numberOfChunks }, (_, index) => {
+    const start = index * chunkSize;
+    return array.slice(index * chunkSize, start + chunkSize);
+  });
+};
+
+const flatten = arr => arr.reduce((acc, current) => acc.concat(current), []);
+
 const fetchParameters = names =>
   ssm
     .getParameters({ Names: names, WithDecryption: true })
     .promise()
     .then(
       data =>
         data.InvalidParameters.length === 0
-          ? Promise.resolve(responseToMap(data))
+          ? Promise.resolve(responseToParams(data))
           : Promise.reject(makeError(data.InvalidParameters))
     );
 
 const replaceParameters = input => paramsMap =>
   input.replace(ssmPattern, match => paramsMap[extractKey(match)]);
 
-module.exports = input =>
-  Promise.resolve(input.match(ssmPattern).map(extractKey))
-    .then(fetchParameters)
+module.exports = input => {
+  const names = input.match(ssmPattern).map(extractKey);
+  const requests = createChunks(keyPerRequestLimit, names).map(fetchParameters);
+  return Promise.all(requests)
+    .then(flatten)
+    .then(paramsToMap)
     .then(replaceParameters(input));
+};